1. This invention generally relates to elevator systems. More particularly, this invention relates to a system for measuring elevator speed within a hoistway.
2. At various times it becomes necessary to measure the speed of an elevator cab moving through a hoistway. One particular need is during elevator installation or adjustment. Conventionally, an elevator technician or mechanic climbs on top of the cab and utilizes a hand-held tachometer to check the speed of the elevator during adjustment or testing. This technique typically requires the technician to hold the tachometer against one of the guide rails within the hoistway while simultaneously attempting to run the elevator using the top of car inspection box. While this technique does provide speed information, there are shortcomings.
3. Efficiency and accuracy of the measurement are sometimes compromised because of the technician""s capabilities for maintaining contact between the tachometer and the guide rail with one hand while operating the top of car inspection box with the other hand. Additionally, there are safety concerns any time that a technician is required to be on top of an elevator cab while it is moving through the hoistway.
4. This invention provides a significant improvement in the field of measuring elevator speeds. With this invention, the technician is no longer required to be on top of the elevator cab during movement.
5. In general terms, this invention is a system for measuring the speed of an elevator cab moving within a hoistway. A system designed according to this invention includes a reflective device that utilizes signal reflections from a structure within the hoistway and provides a signal that is indicative of a speed of the elevator cab. A transmitter associated with the reflective device transmits a signal indicative of the speed. A remotely located receiver receives the transmitted signal and provides an output indicative of the cab speed.
6. In the preferred embodiment, the reflective device is mounted onto the elevator cab and the speed-measuring signals are reflected from a guide rail in the hoistway. The currently preferred embodiment of the remotely located receiver is a handheld device that provides a visual display to a technician for analyzing the speed information.